NASA SBIR 2004 Solicitation


PROPOSAL NUMBER: 04 S5.02-9551
SUBTOPIC TITLE: Mars In Situ Robotics Technology
PROPOSAL TITLE: Mars Gashopper Airplane

SMALL BUSINESS CONCERN (Name, E-mail, Mail Address, City/State/Zip, Phone)
Pioneer Astronautics
11111 W. 8th Ave., Unit A
Lakewood, CO 80215-5516

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Robert Zubrin
11111 W. 8th Ave., Unit A
Lakewood, CO 80215-5516

The Mars Gas Hopper Airplane, or "gashopper" is a novel concept for propulsion of a robust Mars flight and surface exploration vehicle that utilizes indigenous CO2 propellant to enable greatly enhanced mobility. The gashopper will first retrieve CO2 gas from the Martian environment to store it in liquid form at a pressure of about 10 bar. When enough CO2 is stored to make a substantial flight to another Mars site, a hot pellet bed is heated to ~1000 K and the CO2 propellant is warmed to ~300 K to pressurize the tank to ~65 bar. A valve is then opened, allowing the liquid CO2 to pass through the hot pellet bed that heats and gasifies the CO2 for propulsion. The hot gas is piped to a set of thrusters beneath the aircraft, allowing vertical takeoff, after which the gas is shunted off to a primary rearward pointing thruster to generate forward flight speed. The hot gas system is also used for attitude control and main propulsion during landing. The advantage of the gashopper is that it provides Mars exploration with a fully controllable aerial reconnaissance vehicle that can repeatedly land and explore surface sites as well.

The gashopper enables greatly enhanced mobility for robotic Mars exploration vehicles. However the gashopper pellet bed rocket system (PBRS) has many potential important commercial applications in space. Small PBRS thrusters using ammonia could be used for stationkeeping and reaction control system (RCS) propulsion for satellites, as they would provide a non-toxic alternative with comparable performance to hydrazine. PBRS engines could also be used to great advantage to provide stationkeeping propulsion for the International Space Station employing waste CO2 from the life support system as propellant and the PBRS to provide thrust at a much higher level than possible using resistojets.

Another possible commercial application for PBRS technology is for rocket assisted takeoff (RATO) units for small aircraft. The PBRS engine can deliver large amounts of thrust, and because its propellant is CO2 it poses no danger of fire. A PBRS RATO system could be designed as a droppable integrated tank/engine units that would be heated on the airfield using local electric power. Such systems could enable the takeoff of aircraft that are forced to land on short airstrips in emergencies. Since such use of a RATO would avoid loss of an entire aircraft, it could be priced high.